The invention relates to a slide valve closure for the casting of a metal melt, having at least one stationary closure part on a mould or the like, and having a slider plate moveable with respect to this, and a refractory plate unit belonging to it.
In a known slide valve closure for a pressure die casting apparatus according to CH-A-415 972, the riser pipe of a casting furnace is provided at the upper end with a cover plate which seals the casting furnace. On this cover plate there is arranged a slide valve closure with a stationary plate, thereover a slider plate and a block section positioned above the slider plate, on which the mould can be placed.
In another slide valve closure according to DE-A-12 93 962, said closure is mounted on the underside of the mould. The slide valve closure in this case is made up of a lower closing section, the slider plate and a stationary plate located above the slider plate.
These known slide valve closures have the fundamental disadvantage that sealing is not ensured between the slider plate and the part located therebelow or thereabove, with which said slider plate is in sliding contact respectively during opening or closing. As a result, metal melt which usually has a low viscosity can very easily flow between these. Melt pulled in between these plates generally solidifies rapidly which can lead to a blockage of the slider plate after just a few displacement movements.